import { euclidean } from "../metrics/index.js";

import { Matrix } from "../matrix/index.js";

//import { neumair_sum } from "../numerical/index";

/**

* Computes the norm of a vector, by computing its distance to **0**.

* @memberof module:matrix

* @alias norm

* @param {Matrix|Array<Number>|Float64Array} v - Vector.

* @param {Function} [metric = euclidean] - Which metric should be used to compute the norm.

* @returns {Number} - The norm of {@link v}.

*/

export default function (v, metric = euclidean) {

let vector = null;

if (v instanceof Matrix) {

let [rows, cols] = v.shape;

if (rows === 1) vector = v.row(0);

else if (cols === 1) vector = v.col(0);

else throw new Error("Matrix must be 1d!");

} else {

vector = v;

}

const n = vector.length;

const zeros = Float64Array.from({ length: n }, () => 0);

return metric(vector, zeros);

}